A jury convicted Grant of second-degree murder in 2011 and sentenced him to 25 years in prison but that conviction was overturned by the Manitoba Court of Appeal. It ruled the trial judge erred by not allowing the defence to present evidence to the jury that pointed to another possible killer.

Parole and court documents describe the 54-year-old's criminal past, which includes victimizing girls long before he was ever accused of Derksen's murder.

Before that arrest, Grant had served time for three separate assaults on females dating back to the 1980s.

"You have been predatory in your choice of victims, often looking for unsophisticated and vulnerable post-pubescent female children," one Parole Board of Canada review from 2001 said.

1st sexual assault at 14

While Grant has been found not guilty of killing Derksen, he has been candid about his appetite for hurting other girls and young women.

Parole Board of Canada documents report Grant spoke about his first attack, at age 14, when he sexually assaulted a female of an undisclosed age and was sent to a youth detention centre.

As a teen, Grant faced charges for breaking and entering, fraud, forgery, breach of parole, escaping from custody and being unlawfully at large.

Grant targets young women because, he told the parole board, 'they are so trusting.'

His first sexual assault charge as an adult came in 1988. Then in his mid-20s, Grant was accused of sexually assaulting, uttering threats to and unlawfully confining a female, age unknown, who lived with her mother at the time of the trial.

Character witnesses came forward during the trial to present letters defending Grant against the allegations.

One witness, who described herself as a close friend of Grant's, wrote about how he was a caring father to two boys, and said Grant frequently welcomed strangers into his home for a meal and to stay the night if they had nowhere to sleep.

"He has not had many breaks in life," the friend stated. "Mark is not a type of person to hurt another person."

Another female character witness in 1988 stated in a letter that she had known him for seven years and described him as a "bright" and "intelligent," and said she had never known him to be violent. Her letter went on to say his job allowed him to work with disabled people.

Less than two weeks after being released from Bowden Institution in Alberta, Grant was accused of a third sexual assault, in 1994.

Grant, then 32, was convicted of choking and sexually assaulting the female — whose age is not documented — and sentenced to the maximum penalty of 10 years minus time served.

Justice Perry Schulman said in the 1995 decision, "I consider Mr. Grant to be an ongoing threat to the community."

A 2001 Parole Board of Canada decision stated Grant confessed he had raped a drunk stranger and the attack never resulted in charges. The document did not say when the sexual assault occurred.

Targets were 'post-pubescent female children'

The Parole Board of Canada denied Grant parole repeatedly due to concerns he was likely to reoffend because he had shown little progress with "internalizing sex offender relapse prevention concepts" and because he took his psychiatric medications off and on.

Grant has been diagnosed with schizophrenia and in the early 2000s was prescribed medication to control his symptoms, which included medication to control his sexual urges. The parole board noted Grant has frequently attempted suicide.

In 2003, the parole board said that he was likely to 'commit a sexual offence involving a child' before his sentence was completed.

In 2003, the parole board said that he was likely to "commit a sexual offence involving a child" before his sentence was completed.

Grant targets young women because, he told the parole board, "they are so trusting."

After the not guilty decision at the Derksen retrial, Grant's lawyer, Saul Simmonds, expressed sympathy for Candace Derksen's family.

"My heart goes out to anyone who loses a child," Simmonds said. "The sad thing is that sometimes in our zeal to try and find someone responsible, we sometimes go the wrong way. That's what has happened in this case."